Disable JTAG in keyboard init

So that all boards, present and future will have JTAG disabled, even if using a custom matrix

quantum/matrix.c

@@ -148,12 +148,6 @@ uint8_t matrix_cols(void) {
 
 void matrix_init(void) {
 
-    // To use PORTF disable JTAG with writing JTD bit twice within four cycles.
-    #if  (defined(__AVR_AT90USB1286__) || defined(__AVR_AT90USB1287__) || defined(__AVR_ATmega32U4__))
-        MCUCR |= _BV(JTD);
-        MCUCR |= _BV(JTD);
-    #endif
-
     // initialize row and col
 #if (DIODE_DIRECTION == COL2ROW)
     unselect_rows();